Bench drill



June 10 1924;

A. MUEHLMATT BENCH D RILL Filed April 25. 1920 3 Sheets-Sheet 1 A. MU EHLMATT BENCH DRILL June 10V. 1924. 1,497,579

Filed April 25. 1920 5 Sheets-Sheet 2 June 10, 1924. 1,497,579

A. MUEHLMATT v BENCH DRILL Filed April 2s 1920 s sheets-sheet :s

Patented June 10, 1924.

UNITED STATES ADOLJEH MUEI-ILMATT, GF NEVJPORT, KENTUCKY.

BENCH DRILL.

Application lcd April 23, 1920. Serial No. 375,955.

T0 all whom t may concern.'

Be it known that I, ADoLrH MUEHLMATT, a citizen of the United States, and a resident of Newport, Campbell County, Kentucky, have invented a certain new and useful Bench Drill, of which the following is a full, clear, and exact description, reference being had to the drawings forming part of this specication. j

My invention relates to drills, which are employed upon relatively fine work and known as bench drills. For drilling operations such as are required of the jeweler, for example, I know of no small drill press which is calculated to take care of the work, the usual practice being for the operator to hold the work in his hands, and advance it bodily against the revolving' drill, rather than to employ a drilling machine with a movable head.

It is the essential object of my invention to provide a bench drill press, having all of the delicacy of operation required by the bench worker, laboratory worker, jeweler and the like. Among other things I provide `in my new machine for an operating lever which permits of the operator sensing the movement of the drill in the work. I also provide a work support element which permits of special vuses in bench work and jewelry work. In connection with the lubrication of the device I' provide against the chances of oil splattering while providing a complete and very eective lubrication throughout.l `VAnother point is the stop for the movement of the head which is of micrometer nature.

In general `it is my object to make of a bench drill press an instrument of precision, suitable in every detail for the very finest and most delicate work and I accomplish this object and other advantages noted and to be noted, by that certain construction and arrangement of Vparts to be hereinafter more speciically pointed out and claimed. l

In the drawings,

Figure 1 is a side elevation ofA the complete device, same being broken away at several points.

Figure 2 is a plan view of the idler pulley attachment.

Figure 3 is a sectional view taken longi-v tudinally ofthe gear and ratchet shaft,- for operatingg the head supporting rack on the `line 3f ,of Figurel. I v c .c ,i

bar.

Figure l is a perspective view of the guard for the driving pulleys.

Figure 5 is a detail perspective of the working parts for the drill shaft.

Figure 6 is a detail view half in elevation and half in section of a special work holding chuck.

Figure 7 is a like view of another form c oi. special work holding device, these last two devices being substituted forthe plain work supporting table of Figure 1.

Figure 8 is a section on the lines 8, S, of Figure 1.

` The device is shown as provided with a base 1, upon which isVV mounted the electric motor 2. The base has a hollow pedestal l3 on which is mounted the adjustable work table bracket 4 and fixed casting 5 which mounts the various power transmission parts of the'mechanism.

Sliding in the pedestal is the rack bar 6, which at its upper end carries the head 47 of the machine. I/Vithin the hollow baseof the pedestal is set a spring 8 which engages around the lower end 6a of the rack bar and bears against a collar 9 on said bar. This spring tends to press the rack bar, and hence the machine head, upwardly, and the collar is provided with a stop comprising a bushing 10 held within Vthe pedestal by a set screw 10,v which also guides the bar. The bushing is set so that it stops upward movement Awhile the drill shaft is still free to rotate.

f ldounted within a suitable space in the casting 5 and the pedestal is a pinion 11 which meshes with the teeth 6b of the rack rlhis pinion is on a shaft 12, which .is housed in a journal member 13 formed in the cast-ing 5, said shaft having likewise `pinned thereto a` ratchet disk 14;, having facial teeth 1451.

A collar element 15 is set rotatably over the shaft 12, said element having matching ratchet teeth 15a to mesh with the teeth 14a. The collar is pressed resiliently againstthe `ratchet disk 14-by means of a spring.V 18

housed in a cap 16 pinnedto the outer ,end of the shaft.

Ay longhandle 17 which may belong enough toreach down to the `baseof the structure, is set in asuitable socket in the collar element 15, and serves to operate4 the rack and pinion device which effectuate'svthe movement or the head, ,s Since. the., springA 8 6? the una t resists the downward movement of the rack bar, and assists the upward movement, and the situation demanding as it does, delicacy of touch, rather than a quick return of the head from operating position, I prefer that the tension of said spring Abe not very appreciable to the operator as he works the handle'.

Counterclockwise movement of the shaft serves to impel the rack bar downwardly, and clockwise movement of the operating` handle is permitted by the ratchet device, under tension of the spring 18. This tension is suiiicient to jen'ahl'e the ratchet to hold 'during'clockwise movements of the -handle to lift the ra'cl'r loar, lout will give to permit the handle to be adjusted after Ythehead has been hroughtup as far, as it will go.

' The 'advantages ofheing able, toadju'st the handle with'refference tothe shaft 12, is that the operator, having determined the'length of stroke 'lof the handle which is necessary fora certain operation can adjust the handle 'so'that the path of movement thereof is Vmost conf'enijent for him and gives him the greatestsense offrfeel under actuation.

The -downward limitof movementrof the head of the vI'n'ac'hine is provided for by means of avery accuratestop- Thus a pin 20 is mounted vertically and `slid'ahly in the transverse body ofthe head imder control of a finger screw 2l. acting asa set 'screw and bears against ascrew'head 22 of a screw Y `23 th at is threaded in't'o the upper transverse arm'of the casting 5. The screw 23 ispref Ierahly under the control of'a Vlinger screw 24, threaded into the casting `arm -at rightangles to the said screw 23 and carrying at itsi'end a vsuitable engaging member for Vthe threads of the saidscrew 23.

By this construction the stop pin may be adjusted first and then the screw head 22 ad- Y justed'and locked, thereby providing a micrometer-like adjustment for the said heath same vserving jas an [abutment for the stop .pili- .The head of the machine .carries in the sleeve V2,6 thereof` the tool shaft or drill shaft27. This shaft is held at its uppervend Iby ajnut.28 and carries also a washer 29` said washer and the lower portionofthe nut positionedto,remain in arcountersinlr 29a in the sleeve lend.4 A disk 30 carried on the Vshaft is provided with 4a Vthrust `.ball bearing l,31 in a recess 5rL at the lower end "of the sleeve. A

j instances whe'reinfthe drill .shaft lis 'pressed upwardly 'by the operator :as `in reaming out/holes. the hearingl will take "lire 4 riigisia @6inttfreugh a' central hbie'effwhicii tends down to a point adjacent the roller hearing. A radial hole 32 carries oil centrifugally to the upper end of the shaft and a like .hole 32C carries oil to the roller hearing.

The shaft has also a groove 32 running the full length thereof which receives` oil from the holes 32" and 32"'. The recess 31a is made deep enough Jfor the walls thereof to pre vent oil heing dashed centrifngally olf the disk B0 since any oil that thrown will be caught ou the walls of the recess. 'lhis is also true as to the upper recess 2W.

The casting 5 is formed with two arms 3l and 35, which are squared ntl at their ends and provided with ribs 34:5. and 35" respectively, to receive a `guard 3G. This guard has a semi-cylindrical shape andhas ears 37, 38 extending upwardly and downwardly from its median opening. between the ribs and hold the guard firmly in place. there being suitable slots 39 in the upper two ears 'to slide over clamping screws 40.

The two square ends are vertically cored toreceive bushings Lll and 42, through which passes the drill shaft. The bushingsare arranged so that theytermimite just above the lower edge vand hclow the upper edge of the casting arms. The oil which isthrown centrifugally from the shaft in its revolution will thusfbe flung against the walls of the cored out holes in the casting arms and not splatter-ed on the operator or his work. A felt washer 43 `is preferably set inthe recess left atthe top of the upper arm and a gravity washer setoverth'e shaft.

Mounted over the shatt intermediate the two Varms is the double pulley 4A, which is suitably splined to slide in the groove thatruns longitudinally of the drill shaft` this groove heilig in addition to the oil groove. lV'hen driven by `the belt 46. the pulley device serves to rotate the drill shaft hut permitsits movement lmigitudinally to bring it up against and through the work. The shaft has any desired form of chuck 47 for engagingr the desired drill or other tool.

The idler and helttightener pulley device consists of a` hanger 4:8 hinged at the rear of Lthe casting 5. and carrying the two idler gpulleys 49. alt). on a fixed shaft 50. shaft may be oiled through the oil hole 51 Th e and has a `longitudinal groove 51 tocarry the oil tothe pulley and the ends of the shaft at the sides of thehousing formed in the hanger, are protected against oil throwing. The means for accomplishing this are ianged washers 52, held to the ends of the 'shaft by'means of screws I53. The flanges 54 of the washers koverlie the hubs of ...the tw'o pulleys.

lA stop lscrew '551s rovided which Ypositions the hanger at t e desired angle 'for maintaining the belt tightly. Ks shown V'the The ears slide e till lill) belt is preferably actuated by a pulley 56 set on the rotor shaft of the motor. This pulley may be a double pulley, as in the case of the pulley 44, thereby permitting speed regulation by shifting of the belt manually.

The work table, as has been noted, is mounted over the pedestal of the machine by means of a bracket 4. This bracket comprises a split collar adjustable of the pedestal and to be held in adjusted position by means of a hand screw 57 engaging the wings 57a of the split collar. The bracket arm 58 of the work table support may be split and hollow, so that it can be clamped over the cylindrical arm 59 of the table but preferably will have some approved form of turret tool engaging device.

In the simplest form of table, there is a round fiat member 60 having a boss 61 in which the supporting arm is fixed, and having a calibrated scale 61a around that edge of the boss which abuts against the end of the bracket arm. The thumb screw 62 engages a cylindrical bar 62a set in a hole bored laterally through the arm and carries a sleeve 62b thereon. The sleeve and bar are shaped to engage the arm 59 and upon screwing down the screw 62 they will tightly retain the arm 59 between their shaped ends. A suitable mark on the end of the bracketed arm is to be read against the graduations of the scale on the table supporting boss.

As has been stated various forms of work support may be provided to t into the bracket arm. I have illustrated two additional forms, which will form the basis for further applications for patent. As shown in Figure 6 the arm 59@L corresponding to the arm 59 is engaged in the bracket arm, and carries a sleeve 64 for a chuck. The chuck elements comprise the grasping arms `65, under the control of an internally threaded operating head 66. The beveled sleeve 67 that is set between the main sleeve 64 and the grasping arms may be revolved by means of the head, said sleeve 67 having notches 68 therein that are engaged by a spring finger 69. The purpose of this rotary motion is to permit the operator to revolve his work step by step, by releasing the spring linger and turning the whole chuck around in the sleeve 64.

Another form of work holder is shown in Figure 7 wherein the arm 59b corresponds to the arm 59 and the work engaging means is a recessed bar 70 having female centering blocks 7l, 7l2L set into its ends and operating to hold the work down in the recess 72. To operate the blocks I provide the main hand screw 73 and provide the block 71a with a head 74C of its own, this latter wedge block having a threaded portion 75. The conical bearing faces of the blocks will grasp and readily center a metallic bar which is to be acted on through the center of the block 71a.

It is not desired because of my detailed description of a complete embodiment of my invention as given above to do more than illustrate the principles involved in my invention which will be set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, iszl. In a drillpress of the character described, the combination of a standard, a rack in said standard, a sleeve rigidly mounted on said rack, a drill shaft, nonslidably held in said sleeve, and having an anti-friction thrust bearing against upward movement through said sleeve on the standard, a pair of fixed guide sleeves through which the said drill shaft is moved, a driving element on` the drill shaft intermediate the guide sleeves, and a stop for the rack adapted to hold the drill shaft in a position of highest upward adjustment, with the drill shaft out of contact with the standard.

2. In a drill of the character described the combination with a standard of a drill shaft movably supported thereon, said shaft having a plurality of guiding sleeves through which it moves, and a driving element located between said sleeves and means for moving the drill shaft vertically, located above the guiding sleeves, said means being' connected to a rack held by the standard, and a gear meshing with the rack, and a spring held ratchet handle for operating the gear, said spring having sufficient tension to maintain the handle engagement for an upward movement of the rack.

ADOLPH MUEHLMATT. 

